摘要:

Experiments on the flow of liquid helium through glass capillaries ranging in diameter from 0.025 cm. to 0.0036 cm., and with lengths varying from 2 cm. to 26 cm. were carried out. Normal laminar flow was obtained for He I with a viscosity of the order of 10−5 c.g.s. units. For He II it was found that the flow could be expressed as the sum of a laminar flow plus an additional pressure-independent flow. The laminar portion, which obeyed Poiseuille's law, gave a viscosity of the order of 10−3 c.g.s. units. The pressure-independent portion appears to be partially due to "creep" over the top of the reservoir, but there still remains an additional pressure-independent flow through the capillaries. This additional flow depends among other things on the intensity of illumination and is evidently connected with the "fountain" effect.

ISSN:1923-4287    

DOI:10.1139/cjr39a-013

出版商:NRC Research Press    

年代:1939

数据来源: NRC

摘要:

A short description and discussion are given of a thermal conductance apparatus of the guarded hot-box type used by the National Research Laboratories, Ottawa, for the measurement of the thermal conductivity of building materials. Results obtained with this apparatus are compared with hot-plate measurements on the same materials and indicate good agreement between the two methods.

ISSN:1923-4287    

DOI:10.1139/cjr39a-014

出版商:NRC Research Press    

年代:1939

数据来源: NRC